The present invention relates to a method for removing soil from textiles using cyclic dimethylpolysiloxanes. In particular, this invention relates to the use of cyclic dimethylpolysiloxanes for removal of oily/greasy stains from textiles.
Textile products such as fabrics, carpets and upholstery often develop prominent stain spots from inadvertent contact with foodstuff and other materials containing grease and oils. Various organic solvents such as alcohols, petroleum hydrocarbons, and chlorinated hydrocarbons have been used in cleaning compositions adapted for direct application to fabric as spot removers.
Several approaches to formulating spot cleaning compositions are known. For instance, nonresidue cleaners are formulated with volatile components only. After dissolving, mobilizing, and removing the stained material, such formulations are intended to completely evaporate leaving no residue components on the textile. Other cleaning compositions employ a combination of solvent and solid, absorbent particles. The solvent mobilizes the soil and the absorbent solid attracts the soil and solvent to itself. The residue of absorbent solid is intended to be easily removed from the textile by brushing or vacuuming. Yet another approach involves liquid detergent compositions which have been adapted as prewash spot removers. These compositions usually contain concentrated synthetic surfactants with alcohol or other solvents. When used as a prewash spot remover, the nonvolatile surfactant components remain on the textile as a residue which is removed by a conventional home laundry operation. In the aqueous wash, the prewash spot remover composition additionally functions in the manner of a heavy-duty laundry detergent.
While known spot cleaning compositions effectively remove some stains, other types of stains may be unaffected or only incompletely removed by the compositions. In other cases, the cleaning composition itself may damage or leave a residue on the textile in such a way that a visible ring occurs around the treated area. It is an object of the present invention to reduce the problems associated with the prior art cleaning compositions by providing a new method of cleaning stains using volatile silicone fluids that effectively mobilize oil and grease stains, are nondamaging to a wide range of textiles both synthetic and natural, and leave no residue or visible ring on treated textiles.
It is known from U.S. Pat. No. 4,324,595, to remove tacky adhesives from substrates by using octamethylcyclotetrasiloxane fluid to detackify the adhered adhesive. The process is taught to be particularly useful for removing tacky adhesives from human skin, but it is also indicated that the process is applicable to removing tacky adhesives from a wide range of substrates including textiles. However, this patent teaches the removal of only tacky adhesives, it does not suggest removing oil and grease stains with cyclic dimethylsiloxanes.
Stain removing compositions are disclosed in Japanese Patent Publication Kokai No. (1974)-35681, which contain small amounts (0.5 to 10 weight percent) of silicone oil combined with cleaning solvents such as trichlorethane and petroleum hydrocarbons. Although the type of silicone oil employed is not further identified, it is taught that the silicone remains on the fabric after cleaning to provide continuing water repellency and soil resistance for the fabric. Consequently, it is apparent that this publication does not contemplate the use of completely volatile cyclic dimethylpolysiloxanes.
An aerosol type aqueous cleaning composition is disclosed in Japanese Patent Publication Kokai No. (1978)-56203, which contains nonionic surfactant, alkanolamine, glycol ether, alcohol, propellant, and 0.02 to 0.1 weight percent of linear dimethylpolysiloxane with 2 to 7 silicon atoms per molecule. This publication discloses only the use of very low amounts of linear dimethylpolysiloxanes and does not contemplate the use of larger, solvent-effective amounts of the cyclic dimethylpolysiloxanes.
The use of tetraethoxysilane as a solvent for removing grease from textiles is disclosed in Russian Patent Publication 979548-A. However, tetraethoxysilane is not stable in contact with water and may hydrolyze forming alcohol and silica solids.
A process for dry cleaning and waterproofing of fabrics is disclosed in U.S. Pat. No. 3,123,494 which process employs a silicone composition diluted in typical dry cleaning solvents. The silicone compositions recommended are mixtures of linear dimethylpolysiloxane fluids and crosslinked methylsiloxane resins. Excess liquid cleaning mixture is removed from the textiles by centrifuging but retained silicone provided a continuing waterproofing effect on the textile. Again, it is apparent that this publication does not contemplate the use of completely volatile cyclic dimethylpolysiloxanes as a cleaning solvent.
Liquid cleaning compositions for removing dirt and grit from solid surfaces are disclosed in U.S. Pat. No. 2,955,047. The compositions contain surfactants, water, water-miscible organic solvent, and an oil-in-water emulsion of dimethylpolysiloxane oil. The specified siloxanes are linear polymers with viscosities in the range of 200 to 350 centistokes. The siloxane polymer is said to impart a high glossy polish to the treated surfaces by depositing a monomolecular film on the surface. Somewhat similarly, U.S. Pat. No. 2,993,866 teaches an aerosol glass cleaner composition containing isopropanol, fluorochlorohydrocarbon propellants, and linear dimethylpolysiloxane having a viscosity of about 200 centistokes.
An all purpose cleaner composition containing a mixture of surfactants, isopropyl alcohol, and a silicone defoaming agent is disclosed in U.S. Pat. No. 4,311,608. The silicone defoaming agent is an oil-in-water emulsion of dimethylsiloxane polymer.
A cleaner (apparently a wiper type) impregnated with a composition containing mineral oils or alcohols with organopolysiloxanes is disclosed in Japanese Patent Publication Kokai No. (1975)-161059. The organopolysiloxanes are characterized by having a viscosity of not more than 30 centipoise at 20.degree. C.